Tubular joints in the past have used a variety of configurations and seals. Some joints have had a tapered sealing surface on the interior of the end of each tubular member and included a metal seal ring which has a triangular cross-section with the base of the triangle being the inner surface of the ring and forming the extension of the interior of the tubular members.
In one type of flanged joint of the prior art as disclosed in U.S. Pat. No. 1,567,813, the ring gasket or seal ring is provided with upper and lower annular grooves which are in communication with each other by means of axial holes drilled through the ring and also are in communication with the interior of the pipe joint through radial holes drilled from the central interior of the ring into the axial holes. The patent asserts that the joint pressure is conducted to the annular grooves to cause the ring to be wedged more tightly into the sealing grooves in the face of the flanges.
One of the problems with this joint in tubular well members is the problem of erosion or cutting of the tapered seat surface of the tubular member when the joint develops a leak. Correction of the leak requires resurfacing of the tapered sealing surface of the tubular member and replacement of the seal ring. Sometimes the lower tubular member is the one which requires resurfacing. Recovery of such lower member from a well is expensive and time consuming. The alternative is to remachine the tapered surface in the well which is also difficult and expensive.